{
    type Student = {
        a?: number, 
        b: string,
        fn: (n:number) => void,
        fn2(c:string):string
    }
    
    const obj1: Student = { b: '1', fn: n => {console.log(n)}, fn2(c){return c}}


    const obj2: Student = {a: 1,  b: '2', fn: n => {console.log(n)}, fn2(c){return c}}


    function f (obj:Student){
        obj.
    }


    // const obj = { a: 1, b: '1', fn: n => {console.log(n)}, fn2(c){return c}}

    // obj.fn2('abc')

    // const obj = {
    //     fn() {},
    //     fn1:function(){},

    //     fn2:() => {

    //     }
    // }
}